#ifndef THREADPOOL_H
#define THREADPOOL_H

#include <list>
#include <cstdio>
#include <exception>
#include <pthread.h>
/*线程同步类*/
#include "../locker/locker.h"

/*半同步/半反应堆线程池实现，模板参数T是任务类*/
template<typename T>
class threadpool
{
public:
    /*参数thread_number是线程池中线程的数量，max_requests是请求队列中最多允许的、等待处理的请求的数量*/
    threadpool(int thread_number = 8, int max_requests = 10000);
    ~threadpool();
    /*往请求队列中添加任务*/
    bool append(T *request);

private:
/*工作线程运行的函数，不断从工作队列中取出任务并执行*/
    static void* worker(void *arg); //C++中pthread_create第三个藏书必须指向静态函数
    void run();

private:
    int m_thread_number;    //线程池中线程数
    int m_max_requests;     //请求队列中允许的最大请求数
    pthread_t* m_threads;   //描述线程池的数组，其大小为m_thread_number
    std::list<T *> m_workqueue; //请求队列
    locker m_queuelocker;   //保护请求队列的互斥锁
    sem m_queuestat;        //是否有任务需要处理
    bool m_stop;            //是否结束线程
};

template <typename T>
threadpool<T>::threadpool(int thread_number, int max_requests) : 
    m_thread_number(thread_number), m_max_requests(max_requests), m_stop(false), m_threads(NULL)
{
    if ((thread_number <= 0) || (max_requests <= 0))
    {
        throw std::exception();
    }

    m_threads = new pthread_t[m_thread_number];
    if(!m_threads)
    {
        throw std::exception();
    }
    /*创建thread_number个线程，并将它们设置为脱离线程*/
    for (int i = 0; i < thread_number;++i)
    {
        if (pthread_create(m_threads + i, NULL, worker, this) != 0)
        {
            delete[] m_threads;
            throw std::exception();
        }
        if(pthread_detach(m_threads[i]))
        {
            delete[] m_threads;
            throw std::exception();
        }
    }
}

template< typename T >
threadpool< T >::~threadpool()
{
    delete[] m_threads;
    m_stop = true;
}

template< typename T >
bool threadpool< T >::append(T* request)
{
    /*操作工作队列时要加锁，因为它被所有线程共享*/
    m_queuelocker.lock();
    if(m_workqueue.size()>m_max_requests)
    {
        m_queuelocker.unlock();
        return false;
    }
    m_workqueue.push_back(request);
    m_queuelocker.unlock();
    m_queuestat.post();
    return true;
}

template< typename T >
void* threadpool< T >::worker(void* arg)
{
    threadpool *pool = (threadpool *)arg;
    pool->run();
    return pool;
}

template <typename T>
void threadpool<T>::run()
{
    while(!m_stop)
    {
        m_queuestat.wait();
        m_queuelocker.lock();
        if(m_workqueue.empty())
        {
            m_queuelocker.unlock();
            continue;
        }
        T *request = m_workqueue.front();
        m_workqueue.pop_front();
        m_queuelocker.unlock();
        if(!request)
        {
            continue;
        }
        request->process();
    }
}
#endif
